Over the years, many attempts were made to treat or reuse the cuttings from vertically driven oil wells in on shore field operations. The disposal of these oil-covered cuttings has always been a problem for drillers but most of time drillers were just putting them into pits and covering the pits up with earth. For oil wells that were drilled onshore, there was no single process that proved to be economically viable and the use of pits continued. However, for offshore drilling operations, the situation was entirely different.
A number of attempts were made to thermally treat the oil cuttings, in vertically mounted Herreshoff kilns but these attempts caused the opening and closing gates to become thermally distorted due to extensive temperature differentials and the cyclical nature of the operations. All of these various attempts ultimately failed and drillers were forced to put these oil-covered cuttings in containers and ship them to shore locations for disposal in pits. If these oil-covered cuttings were accidentally, allowed to be dumped at sea, they would create a surface film or sheen that would be very costly to recover or remove with pontoons or with absorbents.
For more than eighty years recovering Kerogene, with the use of oil-shale retorting, as a “Brute Force Process”, has been practiced in Estonia and in Spain. As a result of this practice, mountains of spent shale or Nahcolites remain in these countries. In Rifle, Colo. TOSCO, (The Oil Shale Company) vertically configured demonstration plants were built in Rifle, Colo. and near Porto Allegre in Brazil. Both operations failed for the same differential temperature problems and TOSCO was sold to new investors. In the nineteen sixties and nineteen seventies Occidental oil, Exxon and others experimented with the underground recovery of kerogene as a transportation fuel. The whole program collapsed when the world price of crude oil dropped and the recovery of kerogene became uneconomical.
The reuse of water and the disposal of hydrocarbon coated drilling cuttings, both onshore, and more importantly, offshore, has always been an environmental problem for all companies in the oil and gas business. Onshore, the problem has been handled by the disposal of the cuttings by having pits which are then covered by dirt and then abandoned. Offshore the Problem could be more serious because if cuttings are allowed to drop in the water it leaves an oil residue or leaves a fine “sheen” on the surface of the water which has to be removed by using Pontoons or absorbents. The recovery of Barite and Bentonite materials, which are used in the operations both offshore and drilling onshore, requires mud mixtures that are valuable to a drilling company. The recovery of the water, which is used to carry these materials to the drill bit, can also be valuable in many arid areas in the world.
Therefore, an object of further examples is to economically address and satisfactorily resolve some of the major environmental concerns that are of industry-wide importance. Objects of still further examples are to eliminate the need for brine disposal wells, eliminate or minimize the need for pits, the recovery of all flow-back or produced water for reuse in subsequent hydraulic fracturing operations, and the recovery of drilling mud ingredients. Examples of the invention provide technically sound and economically viable solutions to many of the public safety issues that have concerned the industry.